The state of Utah offered a tailored defense of its ban on same-sex marriage, arguing its laws are all about the long-term interests of children.

In a brief filed late Monday evening with the 10th Circuit Court of Appeals, Utah defined marriage as “principally a child-centered institution, one focused first and foremost on the welfare of children rather than the emotional interests of adults,” the brief stated.

That definition is not designed to demean other family structures “any more than giving an ‘A’ to some students demeans others.” But redefining marriage in “genderless” terms likely would result in lower reproductive rates and fewer children being raised in the ideal environment provided by biological, opposite-sex parents, according to the filing.

Attorneys for the three same-sex couples who are challenging Utah’s ban on same-sex marriage have until Feb. 25 to file a response, and the state’s final filing must be submitted by March 4.

The state argued that U.S. District Court Judge Robert J. Shelby’s Dec. 20 decision overturning the state’s ban on same-sex marriage misinterpreted legal precedents in two prevailing cases — one that upheld the right of states to define marriage and, in the United States v. Windsor case, that the federal government cannot interfere with that state decision-making authority.

The state also said Shelby erred in finding same-sex couples sought access to a fundamental right; that that right is implicit in notions of liberty and autonomy; that history and tradition were “insufficient reasons” for a ban on gay marriage; and in comparing Utah’s marriage laws to anti-miscegenation laws.

Limiting marriage to one man and one woman, as Utah and 32 other states do, fulfills a compelling governmental interest rooted in tradition, social science and religion, the brief stated.

The attorneys said that while the state endorses no religious beliefs about marriage, its laws are supported by approximately 20 of the 25 largest faith communities in Utah who “understand marriage and sexuality as gifts from God” and primarily designed to bear and raise children.

Upending that understanding of marriage would create the potential for “religion-related strife,” it stated, impacting rights of religious organizations or members to carry out faith-based or business activities.

Governments face a “perennial challenge” to formally link mothers and fathers to maximize the welfare of children, it stated.

“Marriage between the man and woman who create a child provides that essential link,” according to the brief, and encourages those parents to set aside their own personal desires for the benefit of their children.

But Utah has “steadfastly” reserved social recognition of marriage for man-woman marriage “so as to guide as many procreative couples as possible into the optimal, conjugal childrearing model.”

And that model is working, the brief stated, as reflected by Utah having the lowest percentage of unwed births in the nation, the highest percentage of children being raised by both parents and low child-poverty rates.

Redefining marriage to include same-sex couples would “tend to encourage more parents to raise their existing biological children without the other biological parent.” The state lists six other possible negative outcomes of such a move, including more out-of-wedlock births; increased divorce rates; increased nonmarital sexual activity; more children being raised by same-sex parents; make it difficult to bar other “innovations” such as group marriage; and decreased interest in marriage.

Utah also has a high birthrate, slightly above the replacement rate. In comparison, fertility and birthrates are “markedly lower” in nations and states that have embraced same-sex marriage, the court filing stated.

Oral arguments are scheduled for April 10 in Denver. The three-judge panel that will hear the case — as well as an appeal from the state of Oklahoma involving a similar ban — will be picked 10 days before the hearing.